textproduct: Quad Cities

KEY MESSAGES

- A heat advisory has been issued along and south of a Sigourney, IA to Aledo, IL. Heat indices of 100 to 105 are expected. Across the remainder of the area, heat indices of 95 to 100 can be expected.

- There is a Marginal, level 1 out of 5, risk for severe storms mainly for tonight. The most likely time frame is 10 PM to 4 AM with damaging winds being the primary risk.

- Wednesday and Thursday are primed for numerous severe storms. There is an Enhanced, level 3 out of 5, risk for severe storms each day. There is a weak signal suggesting two rounds of storms Wednesday into Wednesday night followed by possibly two rounds on Thursday.

SHORT TERM /THROUGH TONIGHT/

Issued at 157 AM CDT Tue Jun 9 2026

Light winds and wet ground should allow some fog to develop through sunrise. High level clouds moving in from the Plains may put a damper on how much fog develops. Low lying areas and river valleys should be prime to see some fog development. Weak warm advection is expected to keep some showers persisting through sunrise north of Highway 30.

Heat and humidity will surge into the area today. Cloud cover does raise questions as to how warm it will get (there has been a slight negative delta on temperatures the past several days). With dew points in the 70s, peak afternoon heat indices look to be 95 to 100. The exception is along and south of a line from Sigourney, IA to Aledo, IL. In this area peak heat indices of 100 to 105 are expected and a heat advisory has been issued.

A subtle but weak boundary across the south third of the area will allow dew points to pool and potentially reach the mid 70s or slightly higher. Thus locally, peak afternoon heat indices may briefly rise above 105.

Forcing this afternoon is weak so a majority of the area will see no rain. The south third of the area is another story. The presence of the weak boundary and a potential interaction with an outflow boundary from the nocturnal convection across Missouri may result in some isolated showers and storms that dissipate with sunset.

Tonight could be interesting.

Storms are forecast to fire shortly after sunset in central to northern Iowa and then ride the edge of the heat dome. Progged winds aloft should result in an easterly or east northeast movement. Depending upon where storms initiate, areas north of Highway 30 would have the better chances to see storms; potentially strong to severe.

Right now 11 PM to 5 AM looks to be prime time for any nocturnal storms. If severe storms occur, damaging winds would be the primary risk. Hail would be a secondary risk.

LONG TERM /WEDNESDAY THROUGH MONDAY/

Issued at 157 AM CDT Tue Jun 9 2026

Wednesday/Wednesday night Assessment...high (70-80%) confidence for strong to severe storms

Wednesday will be another hot and humid day. Nocturnal convection from Tuesday night will dictate if any heat headlines will be needed. Right now heat indices look to be right around 100 degrees across the entire area.

There are internal signals from the various models suggesting two possible rounds of severe storms Wednesday into Wednesday night. The much higher risk will be with the second round.

If two rounds of storms occur, the timing of the first round looks to be 10 AM to 4 PM. Damaging winds and hail would occur with the first round of strong to severe storms.

The greater risk of severe storms will be with round two; roughly from 5 PM Wednesday through 2 AM Thursday.

All parameters are in place for initial storm development to be discrete supercells. All severe modes will be possible during this phase, but favoring strong tornadoes and very large hail. The individual storms will grow upscale into a line. When this occurs, the severe risk will transition to damaging winds, potentially 70+ mph, and weaker spin up tornadoes.

Thursday/Thursday night Assessment...high (70-80%) confidence for more strong to severe storms

The models agree that more strong to severe storms will be seen Thursday into Thursday evening. Again depending upon the model solution, there may be one or two rounds of strong to severe storms.

There are some model solutions showing a nocturnal storm complex arriving mid to late morning. If correct, this complex would be in a decaying phase but would be capable of isolated damaging winds and hail.

Like Wednesday, the higher severe risk would be during the afternoon and evening.

Nearly all model solutions show discrete supercells developing along or west of the Mississippi by early afternoon. All severe modes will be possible with the discrete storms, but favoring large hail and tornadoes.

Along or just east of the Mississippi the individual storms will grow upscale into another line. When this transition occurs, the severe risk will be damaging winds, possibly 70+ mph, and weaker spin up tornadoes.

Once the main line of storms passes, lingering storms will continue into Thursday evening before dissipating.

AVIATION /12Z TAFS THROUGH 12Z WEDNESDAY/

Issued at 635 AM CDT Tue Jun 9 2026

Areas of low stratus and/or fog with IFR to LIFR conditions will begin the period at DBQ and MLI before gradual improvement occurs mid to late morning (around or after 14z). CID and BRL will start the period with VFR conditions, but can't rule out a brief bout of MVFR visibility prior to 14z. Thereafter, abundant low level moisture and heating should promote broken stratocu deck with initial MVFR bases lifting to VFR this afternoon. An isolated shower or storm is possible 19z to 02z, but too low of probability for any mention. A somewhat better chance for a storm (30-40%) will arrive after 04z through 08z mainly for the TAF sites near to north of I-80, and have continued PROB30 mention for TSRA.

DVN WATCHES/WARNINGS/ADVISORIES

IA...Heat Advisory from 1 PM this afternoon to 9 PM CDT this evening for IAZ076>078-087>089-098-099. IL...Heat Advisory from 1 PM this afternoon to 9 PM CDT this evening for ILZ024>026-034-035. MO...Heat Advisory from 1 PM this afternoon to 9 PM CDT this evening for MOZ009-010.